CDF Class Reference

#include <histogram.h>

Collaboration diagram for CDF:

Public Member Functions
void	calculateCDF (MultidimArray< double > &V, double probStep=0.005)
	Calculate the CDF of V with a probability step of 0.005 (p is between 0 and 1) More...
double	getProbability (double x)
	Get the probability Pr{V<=x}. More...

Public Attributes
MultidimArray< double >	x
MultidimArray< double >	probXLessThanx
double	minVal
double	maxVal

Detailed Description

Cumulative density function. This function computes a table with the cumulative density function

Definition at line 365 of file histogram.h.

Member Function Documentation

calculateCDF()

void CDF::calculateCDF	(	MultidimArray< double > &	V,
		double	probStep = 0.005
	)

Calculate the CDF of V with a probability step of 0.005 (p is between 0 and 1)

Definition at line 258 of file histogram.cpp.

{
    double *ptr=&DIRECT_MULTIDIM_ELEM(V,0);
    size_t N=MULTIDIM_SIZE(V);
    std::sort(ptr,ptr+N);
    minVal = ptr[0];
    maxVal = ptr[N-1];

    int Nsteps=(int)round(1.0/probStep);
    x.resizeNoCopy(Nsteps);
    probXLessThanx.resizeNoCopy(Nsteps);
    int i=0;
    for (double p=probStep/2; p<1; p+=probStep, i++)
    {
        size_t idx=(size_t)round(p*N);
        A1D_ELEM(probXLessThanx,i)=p;
        A1D_ELEM(x,i)=ptr[idx];
    }
}

getProbability()

double CDF::getProbability

(

double

x

)

Get the probability Pr{V<=x}.

Definition at line 280 of file histogram.cpp.

{
    if (xi>maxVal)
        return 1;
    else if (xi<minVal)
        return 0;
    else
    {
        size_t N=XSIZE(x);
        if (xi<DIRECT_A1D_ELEM(x,0))
            return INTERP(xi,minVal,0.0,DIRECT_A1D_ELEM(x,0),DIRECT_A1D_ELEM(probXLessThanx,0));
        else if (xi>DIRECT_A1D_ELEM(x,N-1))
            return INTERP(xi,DIRECT_A1D_ELEM(x,N-1),DIRECT_A1D_ELEM(probXLessThanx,N-1),maxVal,1.0);
        else
        {
            int iLeft=0;
            int iRight=N-1;
            while (iLeft<=iRight)
            {
                int iMiddle = iLeft+(iRight-iLeft)/2;
                if (xi>=DIRECT_A1D_ELEM(x,iMiddle) && xi<=DIRECT_A1D_ELEM(x,iMiddle+1))
                {
                    if (DIRECT_A1D_ELEM(x,iMiddle)==DIRECT_A1D_ELEM(x,iMiddle+1))
                        return 0.5*(DIRECT_A1D_ELEM(probXLessThanx,iMiddle)+DIRECT_A1D_ELEM(probXLessThanx,iMiddle+1));
                    else
                        return INTERP(xi,DIRECT_A1D_ELEM(x,iMiddle),  DIRECT_A1D_ELEM(probXLessThanx,iMiddle),
                                         DIRECT_A1D_ELEM(x,iMiddle+1),DIRECT_A1D_ELEM(probXLessThanx,iMiddle+1));
                }
                else if (xi<DIRECT_A1D_ELEM(x,iMiddle))
                    iRight=iMiddle;
                else
                    iLeft=iMiddle;
            }
            // std::cout << "It should never reach here" << std::endl;
        }
    }
    return 0.0;
}

Member Data Documentation

maxVal

double CDF::maxVal

Definition at line 370 of file histogram.h.

minVal

double CDF::minVal

Definition at line 370 of file histogram.h.

probXLessThanx

MultidimArray<double> CDF::probXLessThanx

Definition at line 369 of file histogram.h.

x

MultidimArray<double> CDF::x

Definition at line 368 of file histogram.h.

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The documentation for this class was generated from the following files:

• xmippCore/core/histogram.h
• xmippCore/core/histogram.cpp